The invention relates generally to information processing devices and processes. In particular, the invention relates to information processing devices and processes that automatically recognize an identification code printed on one or more pages within a collection of pages (e.g., a book, notebook, writing pad, flip chart, stack of sheets of paper, etc.) (hereinafter a xe2x80x9cbookxe2x80x9d), on a book cover, and surface below the book.
Bar code readers are known in the art and generally come in one of two forms: (1) a scanning laser or charge coupled device (CCD) that is pointed at a bar code while depressing a trigger; and (2) a wand that is swept over a bar code. These devices suffer from a number of limitations for solving the problems addressed by the present invention (e.g., the ability to automatically recognize an identification code printed on one or more pages within a collection of pages). First, known bar code readers require manual input from the user such as pointing, or swiping the instrument over the code. Second, known devices require moving parts which increase the cost and complexity of manufacture, while decreasing reliability. Third, these known devices are designed to identify a bar code in a variety of orientations, making them an overly complex solution for identifying a code in a relatively fixed position with respect to the reader. Fourth, such devices use a visible light source which can disturb the user, or others in the vicinity. Fifth, these device use a scanning laser or a much larger and more expensive sensor array (e.g., 2048xc3x971) than needed for some of the applications addressed by the present invention.
Other known page identification systems use black-and-white or colored squares or stripes (hereinafter xe2x80x9cblocksxe2x80x9d) as the printed codes rather than bar codes, as described in L. J. Stifelman, Augmenting Real World Objects: A Paper-Based Audio Notebook, In the Proceedings of CHI ""96, ACM-SIGCHI, 1996 (xe2x80x9cStifelman 1996xe2x80x9d); L. J. Stifelman, The Audio Notebook: Paper and Pen Interaction with Structured Speech, Doctoral Dissertation, Massachusetts Institute of Technology, September 1997 (xe2x80x9cStifelman 1997xe2x80x9d); and U.S. Pat. No. 4,884,974 to DeSmet (xe2x80x9cDeSmetxe2x80x9d).
These systems, however, have also suffered from a number of limitations. First, the systems do not scale well because of the space required for the blocks representing the codes. Each block represents only one bit of information. Thus, in Stifelman 1997, eleven printed code bits required five inches in width along the bottom of a notebook page. Second, the system is composed of discrete sensors and therefore requires one sensor for every bit of information. This requirement limits the amount of information that can be encoded, and makes the system expensive. Third, the sensor mechanism impedes a user""s handwriting movements causing a portion of the page to be unusable. Fourth, the sensors must be precisely aligned with the code on a page to perform properly.
Additional limitations of Stifelman 1996 and DeSmet include the following. First, the systems rely on ambient light, so performance is degraded under dark conditions. Performance is also degraded under very bright conditions since the sensors can be saturated. Second, the sensors can be blocked or shadowed by the user""s hand or pen, degrading the performance of the detector.
Additional limitations of Stifelman 1997 include the following. First, each discrete sensor must be activated and read one at a time to conserve power. Second, the system cannot be exposed to any ambient light. Ambient light (e.g., bright sunlight) would saturate the sensors and cause false readings. Third, the sensors need to be positioned directly over the page code. The sensors are embedded inside of a ledge that is positioned over the bottom of a notebook. This causes several problems: (1) a book must be slid in and out under the ledge to turn pages; (2) a user cannot rest his/her hand on the notebook or table while writing. Since the ledge was placed over the bottom portion of the notebook, the user must place his/her hand over the ledge. This makes writing in the book, particularly on the lower portion of the page closest to the ledge, difficult and uncomfortable.
Limitations of a system described in J. Rekimoto and K. Nagao, The World through the Computer: Computer Augmented Interaction with Real World Environments, ACM User Interface Software Technology (UIST) Conference Proceedings, 1995 (xe2x80x9cRekimotoxe2x80x9d) include the following. First, Rekimoto requires manual operation by a user. A user must point a camera at the code, and a video camera is an expensive solution. Second, color codes are more expensive to print than a black-and-white bar code and require the availability of a color printer. Third, as stated above, the codes do not scale well. The number of detectable identification codes is limited by the size of the codes. Also, each code stripe represents only one bit of information (stripes are one of two colors, and of equal size).
Another related area known in the art includes electronic books, which modify book pages for identification purposes by putting tabs on pages, cutting out notches, or other similar means. For example, U.S. Pat. No. 4,862,497 to Seto et al (xe2x80x9cSetoxe2x80x9d); U.S. Pat. No. 5,485,176 to Ohara et al. (xe2x80x9cOharaxe2x80x9d); and U.S. Pat. No. 4,809,246 to Jeng (xe2x80x9cJengxe2x80x9d) use photo sensors to sense the presence or absence of a tab on the edge of each page. Similarly, Ohara uses notches instead of tabs, and Jeng additionally requires a button to be pushed whenever a page is turned. The systems described in these patent have several limitations. First, tabs or notches must be cut into pages, and the pages must be rigid or stiff. Second, one sensor is needed for each page. This limits the number of pages that can be coded. With more pages, additional sensors are required, and more space needed for them. Also, each additional sensor adds an additional cost. Third, the tabs must be reflective (white or metal) or opaque.
Other electronic books have used magnets or switches embedded in book pages for page identification. See, for example, U.S. Pat. No. 5,417,575 to McTaggart (xe2x80x9cMcTaggartxe2x80x9d); U.S. Pat. No. 5,631,883 to Li (xe2x80x9cLixe2x80x9d); and U.S. Pat. No. 5,707,240 to Haas et al. (xe2x80x9cHaasxe2x80x9d). McTaggart uses electronics embedded in laminated pages. Electromagnetic switches on pages are used to detect which page is open. Li uses conductive stripes on pages and electromechanical contacts which are prone to failure (e.g., due to dirt on contacts) and require manual operation (i.e., the user touches a button to open/close the contact mechanism). The conductive stripes also have to be exactly aligned with the contacts. Also, turning pages can be difficult since the contacts come down over the page. Haas detects the position of pages using magnets embedded in the page. In each of these systems, the book must be specially produced (i.e., it cannot be printed using standard book printing techniques) and can be expensive to manufacture.
Another area known in the art includes devices for capturing writing on forms. See, for example, U.S. Pat. No. 5,629,499 to Flickinger et al. (xe2x80x9cFlickingerxe2x80x9d); U.S. Pat. No. 5,734,129 to Belville et al. (xe2x80x9cBelvillexe2x80x9d); U.S. Pat. No. 5,627,349 to Shetye et al. (xe2x80x9cShetyexe2x80x9d); and U.S. Pat. No. 5,243,149 to Comerford et al. (xe2x80x9cComerfordxe2x80x9d). Flickinger and Shetye describe a device which secures a form to the device using a clip at the top or bottom. Flickinger suggests that a bar code reader could be embedded in the clip that could automatically read a code on the form. However, the design of this component is not disclosed, and it appears that such a design would be limited because the clip would have to be positioned directly over a form to identify it. Thus, the user would have to lift the clip manually and insert a sheet. It also appears that this design would not generalize for use with a book or notebook, where a user is accustomed to turning pages freely without clipping them in and out. Comerford describes a device where documents are read into the system using a scanner that is slid over the page. The scanner must be manually operated by the user, requires contact with the paper, and is expensive.
U.S. Pat. No. 4,636,881 to Brefka et al. (xe2x80x9cBrefkaxe2x80x9d) uses infrared sensors to detect when a page is turned. This is limited to detecting only relative movement of pages (i.e., previous page, next page) and cannot identify an exact page number. If two or more pages are turned at once, this approach does not work properly.
The invention offers several advantages over the art. The objects and advantages of the invention include the following. One object of the invention is to provide an apparatus that does not require manual operation by a user (e.g., button pushing, pointing an instrument at a code, swiping an instrument over a code). Another object is to provide an apparatus with no moving parts and a minimal number of components, making it inexpensive and simple to manufacture. Yet another object is to provide an apparatus that operates reliably under variable lighting conditions, i.e., from bright light to complete darkness. Still another object is to provide an apparatus that automatically adapts to various light levels.
Another object of the invention is to provide an apparatus that allows multiple pages to be turned at once and does not require sequential page turning. Yet another object is to provide an apparatus that includes an optical sensor and related components that can operate unobtrusively at a distance from the book, and that do not need to be directly looking down over a page and do not require physical contact with the book. Still another object is to provide an apparatus that does not impede the user""s hand movements when writing or gesturing in the book.
Another object of the invention is to provide an apparatus that does not impede page turning by the user. Yet another object is to provide an apparatus that allows book pages to be turned without removal of the book from the receiving surface of the apparatus. Still another object is to provide an apparatus that does not generate false readings when an external object, such as a pen or a finger, partially obscures the optical sensor. Another object is to provide an apparatus that allows minor misalignments of the book in relation to the optical sensor. Yet another object is for the printed code to take up minimal space on the book pages (e.g., only a small corner of a page as opposed to a whole edge of a page). Still another object is to provide an apparatus that only requires a single sensor chip to read a code containing multiple bits of data Another object of the invention is to provide an apparatus that reads identification codes from a relatively fixed position in relation to the optical sensor. Yet another object is to provide an apparatus that uses an invisible light source so as not to disturb a user or others in the vicinity of the apparatus. Still another object is to provide an apparatus with a rapid response time for recognizing the code on a book page with minimal delay following a page turn.
Another object of the invention is to provide an apparatus with identification codes that have built-in redundancy for greater reliability. Yet another object is to provide an apparatus that can operate with a low resolution optical sensor. Still another object is to provide an apparatus that uses identification codes that can be printed on commonly available computer printers (e.g., laser printer, ink jet printer, etc.) or through standard printing techniques (e.g., offset printing).
Another object of the invention is a book with coded pages to identify the pages, or information about a page. Yet another object is a book coded with a width-modulated bar code to ease reading of the code. Still another object is that the codes can identify individual books uniquely, or identify a specific page within a specific book. Yet another object is a code in an upper quadrant of a book so it is out of the way of reading or writing on the page. Another object of the invention is a code along the edge of the book. Yet another object is a code on the cover of the book to identify the cover or uniquely identify an entire book. Still another object is a code on the background area where the book is placed to identify when a book is not present. Still another object is a book using a non-spiral binding to prevent vertical misalignment of pages. Yet another object is a book using round holes for binding to ease page turning.
Another object of the invention is to provide an apparatus that does not require holes, tabs, or notches to be cut in the paper. Yet another object is to provide an apparatus that does not require thick or rigid pages. Still another object is to provide an apparatus that uses a bar code symbology with minimal or no start and stop codes. Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description.
The present invention is a system and method for automatically identifying information (e.g., page numbers) in a book by reading an identification code (e.g., a bar code) printed on each page, on the book cover, and on a surface below the book. The codes on the cover and surface below the book can be used to signal that the book is closed or removed from the system. In addition, the code on the cover can be used to uniquely identify the book, and the codes on the pages can uniquely identify the book and each individual page. Hereafter, the term xe2x80x9cpagexe2x80x9d generically refers to planar surfaces such each side of a leaf in a book, the book cover, a surface below the book, a touch sensitive surface, etc.
In some embodiments, the invention uses an optical sensing technique that allows an optical sensor and related components to be located adjacent to and at a distance from the book so as to not impede the user when turning the pages of the book. The system operates automatically to identify the book and its pages (i.e., no manual operation by a user is required).
The system can operate using ambient light. If, however, ambient light conditions are inadequate for the optical sensor to properly read the codes, the system selectively activates a light source that artificially illuminates the code area. The light source can be non-visible, so that it cannot be seen to anyone looking at, or writing on, the page.
More particularly, the system includes a holder for receiving the book and for keeping it in a substantially fixed position relative to the rest of the system. Once the book is in place, the optical assembly that is located adjacent to the book (such that it does not impede page turning or book insertion and removal) detects the identification code on the page and converts this optical image information into electrical signals for further processing. The optical assembly includes, for example, a reflecting element (e.g. a mirror), a focusing element (e.g. a lens), and an optical sensor. The reflecting element directs light reflected from the identification code onto the focusing element which focuses the light onto the optical sensor so that the optical image can be converted into electrical signals for further processing.
The processor operates on the electrical signals in order to decode them into book and page number information. If the ambient light conditions are insufficient to detect the code, the processor can automatically activate a light source to improve the illumination of the code area on the book. The reflecting element of the optical assembly can direct the light received from the light source onto the identification code on the page.
The identification code can be in the form of a width modulated bar code. The bar code can be a standard bar code or it can be a custom bar code containing for example a single-bar stop code or no start and stop codes whatever. The system is capable of accepting these simplified bar codes, thereby enabling a higher signal-to-noise ratio in the resultant image.